Analytical Approximations for the Capacity of Orthogonal SFBC

Orthogonal space-frequency block coding (OSFBC) combined with orthogonal frequency-division multiplexing (OFDM) has been shown to be a simple and efficient means to exploit the inherent diversity of multiple-input-multiple-output (MIMO) broadband channels. In this paper we derive simple analytical closed-form expressions for the ergodic and outage capacity of OSFBC-OFDM systems assuming that the channel is unknown at the transmitter and perfectly known at the receiver. These expressions are simple functions of the spatial correlation matrices at the channel taps. They clearly reveals the dependence of the capacity on the channel and system parameters. Numerical results show the excellent accuracy of the derived expressions.